Mixtures comprising phosphatides are obtained as by-products in the refining of edible oils and are used, for instance, in foodstuffs, in pharmaceutical products and in cosmetic preparations, especially for their emulsifying properties.
The dry matter of such crude phosphatide mixtures (often referred to as crude or commercial lecithin) as obtained from the refining of, for instance, soyabean or rapeseed oil commonly comprises about 50-65% by weight of phosphatides, 30-40% of neutral glycerides, free fatty acids, sterol compounds, tocopherols etc. and 5-10% of sugars. The phosphatides usually consist mainly of phosphatidylcholine (henceforth called PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI) and phosphatidic acid (PA). Dry, crude vegetable lecithin commonly comprises from about 5 to about 20% by weight of each of these components. Phosphatides that may occur in small amounts in crude lecithin are for example phosphatidylserine, acetylphosphatidylethanolamine and phosphatidylglycerol.
Commonly, by far the major part of the phosphatides in commercial lecithin occurs in the diacyl form. However, small amounts of hydrolysed phosphatides may be present in the lecithin. For example, 1 or 2% of the PC contained in commercial lecithin may occur in the lyso form, i.e. as mono-acylphosphatidylcholine. Henceforth, the lyso and diacyl forms of PC are indicated as LPC and DPC, respectively. Corresponding abbreviations are used to indicate the other phosphatides.
Surface-active compositions comprising phosphatides can suitably be incorporated as emulsifier in edible fat containing products such as for example margarines or low fat spreads. The presence of phosphatides may reduce the spattering that occurs when a fat product, for example margarine, frying oil or a shortening, is used for frying.